diff --git a/build/build.tcl b/build/build.tcl
index 908e95be..d4174d47 100644
--- a/build/build.tcl
+++ b/build/build.tcl
@@ -458,6 +458,10 @@ respond "System?" "ITS\r"
 expect ":KILL"
 respond "*" ":link sys2;tc dc,sys1;ts dcrock\r"
 
+# Zork
+respond "*" ":midas sys3;ts zork_sysen3;zork\r"
+expect ":KILL"
+
 respond "*" ":midas sys1;ts instal_sysen2;instal\r"
 expect ":KILL"
 
diff --git a/src/sysen3/zork.21 b/src/sysen3/zork.21
new file mode 100644
index 00000000..5a4486e7
--- /dev/null
+++ b/src/sysen3/zork.21
@@ -0,0 +1,87 @@
+title ZORK - Stop lusers from losing worse! 
+
+a=:1
+b=:2
+ttyo=:3
+ttyi=:4
+buf=:5
+count=:6
+chcount=:7
+
+define syscal op,args
+.call [setz ? sixbit /op/ ? args ((setz))]
+termin
+
+define type &string
+	movei a,<.length string>
+	move b,[440700,,[ascii string]]
+	syscal SIOT,[%climm,,ttyo ? b ? a]
+	  .lose %lsfil
+termin
+
+zork:	syscal OPEN,[ %clbit,,.uao\%tjdis ? %climm,,ttyo  ;open TTY for output
+		      [sixbit /TTY/]]
+	  .lose %lsfil
+
+	syscal OPEN,[ %clbit,,.uai ? %climm,,ttyi         ;open TTY for input
+		      [sixbit /TTY/]]
+	  .lose %lsfil
+
+	type "C
+There appears before you a huge figure clothed in a dark
+robe. As you shrink back in awe, he speaks:
+
+   ``This is not the machine of the Zork Implementors!''
+
+Then, as suddenly as it appeared, his image dissolves,
+leaving you in darkness. 
+
+As your eyes grow more accustomed to the dim light,
+you notice a clue etched on the wall... It reads:
+
+   No MIT machine supports Zork any longer.
+   Questions may be directed to ZORK@DM.
+		FMZC, GUE 745
+
+Beneath this message a passerby has scrawled:
+
+   No MIT supports DM any longer.
+   Save your breath.
+		FMGC, GUE 799
+
+"
+
+	movei count,5			       ; Initialize input-line counter
+
+line:	movei chcount,0			       ; Move 0 into char counter
+        sosg count			       ; Check for too much time taken
+         jrst dark			       ;  and end if so 
+        cain count,1			       ; If we're about to die
+         type "Your lamp is growing dim.A"   ;  Warn the poor guy
+
+line1:  type ">"			       ; Prompt
+iloop:	.iot ttyi,buf			       ;  read a char
+        cain buf,177			       ; If a rubout
+         jrst rubout			       ;  process rubout
+	cain buf,^M			       ; If a carriage return
+	 jrst newlin			       ;  process text 
+        aos chcount			       ; Increment char count
+        jrst iloop			       ; else read a new char
+
+dark:	type "Your lamp has run out of light. A hungry grue attacks you
+and rips you to pieces. (Next time try Zork on a friendlier system.)
+"					       ; Say bye-bye
+	.logout 1,			       ; kill the game
+
+newlin: jumpe chcount,line1		       ; If no input, no message
+        type "I see no Zork here.A"	       ; Noxious program reply
+	jrst line	                       ; Prompt and Read another line
+
+rubout: skipg chcount			       ; only if chars exist
+         jrst iloop			       ;  Nothing to rub out
+        sos chcount			       ; Decrement char count
+        type "X"			       ;  echo a rubout
+        jrst iloop			       ; Re-enter loop
+
+
+end zork